Prosthodontic restorative systems and techniques are well-known in the prior art. For partially or fully edentulous patients, a dental implant fixture is implanted in a cylindrical bore made in the alveolar ridge crest of a patient's jawbone after the gum tissue has been displaced. The fixture usually includes an internally-threaded cylindrical socket which receives one or more components used for attaching a permanent dental restoration to the fixture. The components typically include an abutment base in the form of a short tubular body having a transverse wall at a first end thereof shaped to mate with the gingival aspect of a transverse surface of the implant fixture. The abutment base has a bore therethrough for receiving an abutment screw used to retain the abutment base to the fixture. A dental restoration, in the form of an anatomical overlay, is adapted to be affixed to the abutment base. One such system is shown in U.S. Pat. No. 4,988,298 to Lazzara et al.
It is also known in the prior art to provide such single-tooth prosthodontic restorations with suitable means for preventing the anatomical overlay from rotating with respect to the remainder of the implant fixture. Such systems are described in U.S. Pat. No. 4,955,811 to Lazzara et al. While the inventions disclosed in the above-identified patents have proven advantageous, such prior art methods and techniques do not address all of the problems associated with permanent dental restoration. One such problem involves the tendency of the various abutment and other retaining and coping screws to reverse or "back-out" of their fittings following installation. Presently, there exists no solution to this problem.
It would therefore be desirable to provide a dental implant restorative system having optional anti-rotational features and wherein retention screws are rigidly secured against rotation to prevent screw reversal during normal use and wear of the system.